Techniques for managing beams in multiple frequency bands

ABSTRACT

Aspects described herein relate to communicating with a base station over multiple frequency bands using a first beam, and switching from the first beam to the second beam during a time period or based on a timing of the reference band. Other aspects relate to transmitting an indication of one or more parameters for determining a reference band of the multiple frequency bands to use as a timing reference for switching beams for communicating over the multiple frequency bands.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present Application for Patent claims priority to Provisional PatentApplication No. 63/063,161, entitled “TECHNIQUES FOR MANAGING BEAMS INMULTIPLE FREQUENCY BANDS” filed Aug. 7, 2020, which is assigned to theassignee hereof and hereby expressly incorporated by reference hereinfor all purposes.

TECHNICAL FIELD

The present disclosure relates generally to wireless communicationsystems, and more particularly, to techniques for managing beams inmultiple frequency bands.

DESCRIPTION OF THE RELATED TECHNOLOGY

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (for example, time, frequency, and power). Examples ofsuch multiple-access systems include fourth generation (4G) systems suchas Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform spread orthogonal frequency division multiplexing(DFT-S-OFDM). A wireless multiple-access communications system mayinclude one or more base stations or one or more network access nodes,each simultaneously supporting communication for multiple communicationdevices, which may be otherwise known as user equipment (UE).

Some wireless communication systems may support communicating overmultiple frequency bands, such as by way of carrier aggregation (CA)where devices can use multiple component carriers (CCs) forcommunications with one another. A base station can configure a UE touse multiple CCs for CA to communicate with the base station or withother base stations. The UE can use a single common beam to beamformantenna resources for communicating over each of the multiple CCs. Inaddition, the UE can switch the common beam to a different common beam,having a different beamforming direction, based on UE mobility (as theUE moves locations with respect to the base station).

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

In some aspects of the disclosure, a method, or an apparatus or acomputer-readable medium to perform the method, are provided. In someaspects, the method includes concurrently communicating with a basestation over multiple frequency bands using a same first beam, andswitching, according to beam switching criteria, from the first beam toa second beam during a time period, where the time period is one of alimited number of time periods during which a user equipment (UE) isallowed to switch the first beam to the second beam within a specifiedduration, or based on a timing reference associated with a referenceband of the multiple frequency bands.

In another aspect, a method includes communicating with a UE overmultiple frequency bands using a first beam to beamform antennaresources for communications over the multiple frequency bands, andtransmitting, to the UE, an indication of one or more parameters fordetermining a reference band of the multiple frequency bands to use as atiming reference for switching beams for communicating over the multiplefrequency bands

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail some illustrative features ofthe one or more aspects. These features are indicative, however, of buta few of the various ways in which the principles of various aspects maybe employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network.

FIGS. 2A, 2B, 2C, and 2D are diagrams illustrating examples of a first5G/NR frame, DL channels within a 5G/NR subframe, a second 5G/NR frame,and UL channels within a 5G/NR subframe, respectively.

FIG. 3 is a diagram illustrating an example of a base station and userequipment (UE) in an access network.

FIG. 4 is a flowchart of an example of a method for determining a timeperiod for switching a common beam in accordance with some aspects ofthe present disclosure.

FIG. 5 is a flowchart of an example of a method for determining areference band for switching a common beam in accordance with someaspects of the present disclosure.

FIG. 6 illustrates an example of a system for configuring a referenceband for switching a common beam in accordance with some aspects of thepresent disclosure.

FIG. 7 shows a block diagram of an example wireless communicationdevice.

FIG. 8 shows a block diagram of an example wireless communication deviceaccording to some implementations.

FIG. 9 shows a block diagram of an example wireless communication deviceaccording to some implementations.

Like reference numbers and designations in the various drawings indicatelike elements

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those of ordinaryskill in the art that these concepts may be practiced without thesespecific details. In some instances, structures and components are shownin block diagram form in order to avoid obscuring such concepts.

Various aspects relate generally to techniques for managing beams inmultiple frequency bands. Some aspects more specifically relate tomanaging a common beam that is used to beamform antenna resources forcommunicating over multiple frequency bands. In some aspects, a userequipment (UE) can use multiple frequency bands, for example, associatedwith multiple configured component carriers (CCs) to communicate with anetwork entity such as a base station or another UE. The UE can beamformantenna resources using a common beam to communicate over each of themultiple frequency bands. As the UE moves location with respect to abase station, or as the communication environment changes (for example,in the presence of signal blocking or reflection by objects), the UE maydesire to change the common beam for improved signal strength andquality when communicating with the base station. Communications overthe multiple frequency bands, however, may not be aligned in time, andas such, switching the common beam based on considerations for a firstfrequency band of the multiple frequency bands, may cause beam failureor otherwise loss of communication on a second frequency band of themultiple frequency bands. For example, if the maximum difference betweena time a first signal is received by the UE in a first frequency bandand a time a second signal is received by the UE in a second frequencyband (“receive time difference (RTD)”) among the multiple frequencybands is greater than a threshold (for example, greater than a period oftime associated with a cyclic prefix (CP)), the UE may fail tosuccessfully receive one or more symbols in at least one of the multiplefrequency bands when the UE (or a network entity) switches the commonbeam.

In some aspects, the UE can determine a limited number of time periodsduring which the UE can perform beam switching of the common beam, suchas to mitigate degradation in communications over the multiple frequencybands. For example, the time periods can correspond to symbols (forexample, orthogonal frequency division multiplexing (OFDM) symbols) overwhich the UE can perform the beam switching of the common beam, wherethe symbols may correspond to a slot containing multiple symbols. Inanother example, the time periods can include collections of symbols,such as one or more slots. For example, the UE can determine to usesymbols associated with a transmission gap that are between uplinksymbols defined for uplink communications and downlink symbols definedfor downlink communications in a slot. In another example, the UE candetermine to avoid using symbols over which synchronization signalblocks (SSBs), physical downlink control channel (PDCCH) search spaces,or reference signals (RSs) are transmitted. In yet another example, theUE can determine to use symbols based on a function of a slot or symbolindex.

In some other aspects, the UE can determine one of the multiplefrequency bands (referred to herein as a “reference band”) to use as atiming reference. The reference band can be the frequency band overwhich the beam switch is performed or otherwise managed. In someexamples, the UE can determine the reference band as a higher priorityband of the multiple frequency bands. In this regard, the base stationand UE can know the beam switch is occurring over particular resourcesof the reference band and can avoid communicating over the referenceband during the beam switch. Communications may continue, however, overthe non-reference bands during the beam switch. Accordingly, the UE candetermine the reference band as a frequency band having a highest signalmetric, a most recently reported signal metric, a lower index (forexample, a lower channel index, such as E-UTRA absolute radio frequencychannel number (EARFCN) index, an index within a configuration ofchannels or bands received from the base station, or other examples), acenter frequency, a most frequent PDCCH search space (for example, achannel having PDCCH configured to occur more frequently than otherchannels), or channels with higher priority than channels in otherfrequency bands, among other examples.

Particular implementations of the subject matter described in thisdisclosure can be implemented to realize one or more of the followingpotential advantages. In some aspects of the present disclosure,limiting the symbols over which the UE can perform common beam switchingcan enable the UE to avoid communication degradation or disruptionotherwise caused on some frequency bands (for example, non-referencefrequency bands) when switching the common beam. In addition, in someaspects, selecting the reference band from the multiple frequency bandsmay enable the UE to prioritize a most used or most desirable frequencyband for performing or managing the beam switching to avoid anunexpected disruption of communications on this frequency band.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, components, circuits,processes, algorithms, among other examples (collectively referred to as“elements”). These elements may be implemented using electronichardware, computer software, or any combination thereof. Whether suchelements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented as a “processing system” thatincludes one or more processors. Examples of processors includemicroprocessors, microcontrollers, graphics processing units (GPUs),central processing units (CPUs), application processors, digital signalprocessors (DSPs), reduced instruction set computing (RISC) processors,systems on a chip (SoC), baseband processors, field programmable gatearrays (FPGAs), programmable logic devices (PLDs), state machines, gatedlogic, discrete hardware circuits, and other suitable hardwareconfigured to perform the various functionality described throughoutthis disclosure. One or more processors in the processing system mayexecute software. Software shall be construed broadly to meaninstructions, instruction sets, code, code segments, program code,programs, subprograms, software components, applications, softwareapplications, software packages, routines, subroutines, objects,executables, threads of execution, procedures, functions, among otherexamples, whether referred to as software, firmware, middleware,microcode, hardware description language, or otherwise.

Accordingly, in one or more examples, the functions described may beimplemented in hardware, software, or any combination thereof. Ifimplemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes computer storage media. Storage mediamay be any available media that can be accessed by a computer. By way ofexample, and not limitation, such computer-readable media can include arandom-access memory (RAM), a read-only memory (ROM), an electricallyerasable programmable ROM (EEPROM), optical disk storage, magnetic diskstorage, other magnetic storage devices, combinations of theaforementioned types of computer-readable media, or any other mediumthat can be used to store computer executable code in the form ofinstructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network 100. The wireless communications system(also referred to as a wireless wide area network (WWAN)) includes basestations 102, UEs 104, an Evolved Packet Core (EPC) 160, and anothercore network 190 (for example, a 5G Core (5GC)). The base stations 102may include macrocells (high power cellular base station) or small cells(low power cellular base station). The macrocells include base stations.The small cells include femtocells, picocells, and microcells.

The base stations 102 configured for 4G LTE (collectively referred to asEvolved Universal Mobile Telecommunications System (UMTS) TerrestrialRadio Access Network (E-UTRAN)) may interface with the EPC 160 throughfirst backhaul links 132 (for example, an S1 interface). The basestations 102 configured for 5G NR (collectively referred to as NextGeneration RAN (NG-RAN)) may interface with core network 190 throughsecond backhaul links 184. In addition to other functions, the basestations 102 may perform one or more of the following functions:transfer of user data, radio channel ciphering and deciphering,integrity protection, header compression, mobility control functions(for example, handover, dual connectivity), inter-cell interferencecoordination, connection setup and release, load balancing, distributionfor non-access stratum (NAS) messages, NAS node selection,synchronization, radio access network (RAN) sharing, multimediabroadcast multicast service (MBMS), subscriber and equipment trace, RANinformation management (RIM), paging, positioning, and delivery ofwarning messages. The base stations 102 may communicate directly orindirectly (for example, through the EPC 160 or core network 190) witheach other over third backhaul links 134 (for example, X2 interface).The third backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. There may be overlappinggeographic coverage areas 110. For example, the small cell 102 a mayhave a coverage area 110 a that overlaps the coverage area 110 of one ormore macro base stations 102. A network that includes both small celland macrocells may be known as a heterogeneous network. A heterogeneousnetwork may also include Home Evolved Node Bs (eNBs) (HeNBs), which mayprovide service to a restricted group known as a closed subscriber group(CSG). The communication links 120 between the base stations 102 and theUEs 104 may include uplink (UL) (also referred to as reverse link)transmissions from a UE 104 to a base station 102 or downlink (DL) (alsoreferred to as forward link) transmissions from a base station 102 to aUE 104. The communication links 120 may use multiple-input andmultiple-output (MIMO) antenna technology, including spatialmultiplexing, beamforming, or transmit diversity. The communicationlinks may be through one or more carriers. The base stations 102/UEs 104may use spectrum up to Y MHz (for example, 5, 10, 15, 20, 100, 400 MHz,among other examples) bandwidth per carrier allocated in a carrieraggregation of up to a total of Yx MHz (x component carriers) used fortransmission in each direction. The carriers may or may not be adjacentto each other. Allocation of carriers may be asymmetric with respect toDL and UL (for example, more or fewer carriers may be allocated for DLthan for UL). The component carriers may include a primary componentcarrier and one or more secondary component carriers. A primarycomponent carrier may be referred to as a primary cell (PCell) and asecondary component carrier may be referred to as a secondary cell(SCell).

Some UEs 104 may communicate with each other using device-to-device(D2D) communication link 158. The D2D communication link 158 may use theDL/UL WWAN spectrum. The D2D communication link 158 may use one or moresidelink channels, such as a physical sidelink broadcast channel(PSBCH), a physical sidelink discovery channel (PSDCH), a physicalsidelink shared channel (PSSCH), and a physical sidelink control channel(PSCCH). D2D communication may be through a variety of wireless D2Dcommunications systems, such as for example, FlashLinQ, WiMedia,Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi accesspoint (AP) 150 in communication with Wi-Fi stations (STAs) 152 viacommunication links 154 in a 5 GHz unlicensed frequency spectrum. Whencommunicating in an unlicensed frequency spectrum, the STAs 152/AP 150may perform a clear channel assessment (CCA) prior to communicating inorder to determine whether the channel is available.

The small cell 102 a may operate in a licensed or an unlicensedfrequency spectrum. When operating in an unlicensed frequency spectrum,the small cell 102 a may employ NR and use the same 5 GHz unlicensedfrequency spectrum as used by the Wi-Fi AP 150. The small cell 102 a,employing NR in an unlicensed frequency spectrum, may boost coverage toor increase capacity of the access network.

A base station 102, whether a small cell 102 a or a large cell (forexample, macro base station), may include or be referred to as an eNB,gNodeB (gNB), or another type of base station. Some base stations, suchas gNB 180 may operate in a traditional sub 6 GHz spectrum, inmillimeter wave (mmW) frequencies, or near mmW frequencies incommunication with the UE 104. When the gNB 180 operates in mmW or nearmmW frequencies, the gNB 180 may be referred to as an mmW base station.Extremely high frequency (EHF) is part of the RF in the electromagneticspectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between1 millimeter and 10 millimeters. Radio waves in the band may be referredto as a millimeter wave. Near mmW may extend down to a frequency of 3GHz with a wavelength of 100 millimeters. The super high frequency (SHF)band extends between 3 GHz and 30 GHz, also referred to as centimeterwave. Communications using the mmW/near mmW radio frequency band (forexample, 3 GHz-300 GHz) has extremely high path loss and a short range.The mmW base station 180 may utilize beamforming to generate beamformedsignals 182 (also referred to as “beams”) with the UE 104 to compensatefor the extremely high path loss and short range. The base station 180and the UE 104 may each include a plurality of antennas, such as antennaelements, antenna panels, or antenna arrays to facilitate thebeamforming. Though base station 102 and mmW base station 180 areseparately shown, aspects described herein with respect to a basestation 102 can relate to, and be implemented by, a mmW base station180.

The base station 180 may transmit a beamformed signal to the UE 104 inone or more transmit directions 182 a. The UE 104 may receive thebeamformed signal from the base station 180 in one or more receivedirections 182 b. The UE 104 may also transmit a beamformed signal tothe base station 180 in one or more transmit directions. The basestation 180 may receive the beamformed signal from the UE 104 in one ormore receive directions. The base station 180/UE 104 may perform beamtraining to determine the best receive and transmit directions for eachof the base station 180/UE 104. The transmit and receive directions forthe base station 180 may or may not be the same. The transmit andreceive directions for the UE 104 may or may not be the same.

The EPC 160 may include a Mobility Management Entity (MME) 162, otherMMEs 164, a Serving Gateway 166, a Multimedia Broadcast MulticastService (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be incommunication with a Home Subscriber Server (HSS) 174. The MME 162 isthe control node that processes the signaling between the UEs 104 andthe EPC 160. Generally, the MME 162 provides bearer and connectionmanagement. All user Internet protocol (IP) packets are transferredthrough the Serving Gateway 166, which itself is connected to the PDNGateway 172. The PDN Gateway 172 provides UE IP address allocation aswell as other functions. The PDN Gateway 172 and the BM-SC 170 areconnected to the IP Services 176. The IP Services 176 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService, or other IP services. The BM-SC 170 may provide functions forMBMS user service provisioning and delivery. The BM-SC 170 may serve asan entry point for content provider MBMS transmission, may be used toauthorize and initiate MBMS Bearer Services within a public land mobilenetwork (PLMN), and may be used to schedule MBMS transmissions. The MBMSGateway 168 may be used to distribute MBMS traffic to the base stations102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN)area broadcasting a particular service, and may be responsible forsession management (start/stop) and for collecting eMBMS relatedcharging information.

The core network 190 may include a Access and Mobility ManagementFunction (AMF) 192, other AMFs 193, a Session Management Function (SMF)194, and a User Plane Function (UPF) 195. The AMF 192 may be incommunication with a Unified Data Management (UDM) 196. The AMF 192 isthe control node that processes the signaling between the UEs 104 andthe core network 190. Generally, the AMF 192 provides QoS flow andsession management. All user Internet protocol (IP) packets aretransferred through the UPF 195. The UPF 195 provides UE IP addressallocation as well as other functions. The UPF 195 is connected to theIP Services 197. The IP Services 197 may include the Internet, anintranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, orother IP services.

The base station may include or be referred to as a gNB, Node B, eNB, anaccess point, a base transceiver station, a radio base station, a radiotransceiver, a transceiver function, a basic service set (BSS), anextended service set (ESS), a transmit reception point (TRP), or someother suitable terminology. The base station 102 provides an accesspoint to the EPC 160 or core network 190 for a UE 104. Examples of UEs104 include a cellular phone, a smart phone, a session initiationprotocol (SIP) phone, a laptop, a personal digital assistant (PDA), asatellite radio, a global positioning system, a multimedia device, avideo device, a digital audio player (for example, MP3 player), acamera, a game console, a tablet, a smart device, a wearable device, avehicle, an electric meter, a gas pump, a large or small kitchenappliance, a healthcare device, an implant, a sensor/actuator, adisplay, or any other similar functioning device. Some of the UEs 104may be referred to as IoT devices (for example, parking meter, gas pump,toaster, vehicles, heart monitor, among other examples). The UE 104 mayalso be referred to as a station, a mobile station, a subscriberstation, a mobile unit, a subscriber unit, a wireless unit, a remoteunit, a mobile device, a wireless device, a wireless communicationsdevice, a remote device, a mobile subscriber station, an accessterminal, a mobile terminal, a wireless terminal, a remote terminal, ahandset, a user agent, a mobile client, a client, or some other suitableterminology.

Referring again to FIG. 1, in some aspects, the UE 104 may include acommunicating component 198 configured to determine one or more timeperiods during which to switch a common beam (for example, one of thebeams 182) for multiple frequency bands over which the UE 104communicates with a base station 102. In another aspect, communicatingcomponent 198 can be configured to determine a reference band to use inperforming the beam switching. In some aspects, the base station 102 mayinclude a configuring component 199 configured to indicate, to the UE104, time periods during which to performing beam switching of a commonbeam for multiple frequency bands, or one or more parameters fordetermining a reference band for performing the beam switching, amongother examples. Although the following description may be described interms of 5G NR and related features, the concepts described herein maybe applicable to other areas or wireless communication technologies,such as LTE, LTE-A, CDMA, GSM, or future communications standards ortechnologies.

FIG. 2A is a diagram 200 illustrating an example of a first subframewithin a 5G/NR frame structure. FIG. 2B is a diagram 230 illustrating anexample of DL channels within a 5G/NR subframe. FIG. 2C is a diagram 250illustrating an example of a second subframe within a 5G/NR framestructure. FIG. 2D is a diagram 280 illustrating an example of ULchannels within a 5G/NR subframe. The 5G/NR frame structure may be FDDin which for a particular set of subcarriers (carrier system bandwidth),subframes within the set of subcarriers are dedicated for either DL orUL, or may be TDD in which for a particular set of subcarriers (carriersystem bandwidth), subframes within the set of subcarriers are dedicatedfor both DL and UL. In the examples provided by FIGS. 2A, 2C, the 5G/NRframe structure is assumed to be TDD, with subframe 4 being configuredwith slot format 28 (with mostly DL), where D is DL, U is UL, and X isflexible for use between DL/UL, and subframe 3 being configured withslot format 34 (with mostly UL). While subframes 3, 4 are shown withslot formats 34, 28, respectively, any particular subframe may beconfigured with any of the various available slot formats 0-61. Slotformats 0, 1 are all DL, UL, respectively. Other slot formats 2-61include a mix of DL, UL, and flexible symbols. UEs are configured withthe slot format (dynamically through DL control information (DCI), orsemi-statically/statically through radio resource control (RRC)signaling) through a received slot format indicator (SFI). Note that thedescription presented herein applies also to a 5G/NR frame structurethat is TDD.

Other wireless communication technologies may have a different framestructure or different channels. A frame (10 ms) may be divided into 10equally sized subframes (1 ms). Each subframe may include one or moretime slots. Subframes may also include mini-slots, which may include 7,4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on theslot configuration. For slot configuration 0, each slot may include 14symbols, and for slot configuration 1, each slot may include 7 symbols.The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. Thesymbols on UL may be CP-OFDM symbols (for high throughput scenarios) ordiscrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (alsoreferred to as single carrier frequency-division multiple access(SC-FDMA) symbols) (for power limited scenarios; limited to a singlestream transmission). The number of slots within a subframe is based onthe slot configuration and the numerology. For slot configuration 0,different numerologies μ 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots,respectively, per subframe. For slot configuration 1, differentnumerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, persubframe. Accordingly, for slot configuration 0 and numerology μ, thereare 14 symbols/slot and 2^(μ) slots/subframe. The subcarrier spacing andsymbol length/duration are a function of the numerology. The subcarrierspacing may be equal to 2^(μ)* 15 kHz, where μ is the numerology 0 to 5.As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and thenumerology μ=5 has a subcarrier spacing of 480 kHz. The symbollength/duration is inversely related to the subcarrier spacing. FIGS.2A-2D provide an example of slot configuration 0 with 14 symbols perslot and numerology μ=0 with 1 slot per subframe. The subcarrier spacingis 15 kHz and symbol duration is approximately 66.7 μs.

A resource grid may be used to represent the frame structure. Each timeslot includes a resource block (RB) (also referred to as physical RBs(PRBs)) that extends 12 consecutive subcarriers. The resource grid isdivided into multiple resource elements (REs). The number of bitscarried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry reference (pilot)signals (RS) for the UE. The RS may include demodulation RS (DM-RS)(indicated as R_(x) for one particular configuration, where 100× is theport number, but other DM-RS configurations are possible) and channelstate information reference signals (CSI-RS) for channel estimation atthe UE. The RS may also include beam measurement RS (BRS), beamrefinement RS (BRRS), and phase tracking RS (PT-RS).

FIG. 2B illustrates an example of various DL channels within a subframeof a frame. The physical downlink control channel (PDCCH) carries DCIwithin one or more control channel elements (CCEs), each CCE includingnine RE groups (REGs), each REG including four consecutive REs in anOFDM symbol. A primary synchronization signal (PSS) may be within symbol2 of particular subframes of a frame. The PSS is used by a UE 104 todetermine subframe/symbol timing and a physical layer identity. Asecondary synchronization signal (SSS) may be within symbol 4 ofparticular subframes of a frame. The SSS is used by a UE to determine aphysical layer cell identity group number and radio frame timing. Basedon the physical layer identity and the physical layer cell identitygroup number, the UE can determine a physical cell identifier (PCI).Based on the PCI, the UE can determine the locations of theaforementioned DM-RS. The physical broadcast channel (PBCH), whichcarries a master information block (MIB), may be logically grouped withthe PSS and SSS to form a synchronization signal (SS)/PBCH block. TheMIB provides a number of RBs in the system bandwidth and a system framenumber (SFN). The physical downlink shared channel (PDSCH) carries userdata, broadcast system information not transmitted through the PBCH suchas system information blocks (SIBs), and paging messages.

As illustrated in FIG. 2C, some of the REs carry DM-RS (indicated as Rfor one particular configuration, but other DM-RS configurations arepossible) for channel estimation at the base station. The UE maytransmit DM-RS for the physical uplink control channel (PUCCH) and DM-RSfor the physical uplink shared channel (PUSCH). The PUSCH DM-RS may betransmitted in the first one or two symbols of the PUSCH. The PUCCHDM-RS may be transmitted in different configurations depending onwhether short or long PUCCHs are transmitted and depending on theparticular PUCCH format used. Although not shown, the UE may transmitsounding reference signals (SRS). The SRS may be used by a base stationfor channel quality estimation to enable frequency-dependent schedulingon the UL.

FIG. 2D illustrates an example of various UL channels within a subframeof a frame. The PUCCH may be located as indicated in one configuration.The PUCCH carries uplink control information (UCI), such as schedulingrequests, a channel quality indicator (CQI), a precoding matrixindicator (PMI), a rank indicator (RI), and HARQ ACK/NACK feedback. ThePUSCH carries data, and may additionally be used to carry a bufferstatus report (BSR), a power headroom report (PHR), or UCI.

FIG. 3 is a block diagram of a base station 310 in communication with aUE 350 in an access network. In the DL, IP packets from the EPC 160 maybe provided to a controller/processor 375. The controller/processor 375implements layer 3 and layer 2 functionality. Layer 3 includes a radioresource control (RRC) layer, and layer 2 includes a service dataadaptation protocol (SDAP) layer, a packet data convergence protocol(PDCP) layer, a radio link control (RLC) layer, and a medium accesscontrol (MAC) layer. The controller/processor 375 provides RRC layerfunctionality associated with broadcasting of system information (suchas MIB, SIBs), RRC connection control (such as RRC connection paging,RRC connection establishment, RRC connection modification, and RRCconnection release), inter radio access technology (RAT) mobility, andmeasurement configuration for UE measurement reporting; PDCP layerfunctionality associated with header compression/decompression, security(ciphering, deciphering, integrity protection, integrity verification),and handover support functions; RLC layer functionality associated withthe transfer of upper layer packet data units (PDUs), error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC servicedata units (SDUs), re-segmentation of RLC data PDUs, and reordering ofRLC data PDUs; and MAC layer functionality associated with mappingbetween logical channels and transport channels, multiplexing of MACSDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs,scheduling information reporting, error correction through HARQ,priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370implement layer 1 functionality associated with various signalprocessing functions. Layer 1, which includes a physical (PHY) layer,may include error detection on the transport channels, forward errorcorrection (FEC) coding/decoding of the transport channels,interleaving, rate matching, mapping onto physical channels,modulation/demodulation of physical channels, and MIMO antennaprocessing. The TX processor 316 handles mapping to signalconstellations based on various modulation schemes (such as binaryphase-shift keying (BPSK), quadrature phase-shift keying (QPSK),M-phase-shift keying (M-PSK), M-quadrature amplitude modulation(M-QAM)). The coded and modulated symbols may then be split intoparallel streams. Each stream may then be mapped to an OFDM subcarrier,multiplexed with a reference signal (such as a pilot) in the time orfrequency domain, and then combined together using an Inverse FastFourier Transform (IFFT) to produce a physical channel carrying a timedomain OFDM symbol stream. The OFDM stream is spatially precoded toproduce multiple spatial streams. Channel estimates from a channelestimator 374 may be used to determine the coding and modulation scheme,as well as for spatial processing. The channel estimate may be derivedfrom a reference signal or channel condition feedback transmitted by theUE 350. Each spatial stream may then be provided to a different antenna320 via a separate transmitter 318TX. Each transmitter 318TX maymodulate an RF carrier with a respective spatial stream fortransmission.

At the UE 350, each receiver 354RX receives a signal through itsrespective antenna 352. Each receiver 354RX recovers informationmodulated onto an RF carrier and provides the information to the receive(RX) processor 356. The TX processor 368 and the RX processor 356implement layer 1 functionality associated with various signalprocessing functions. The RX processor 356 may perform spatialprocessing on the information to recover any spatial streams destinedfor the UE 350. If multiple spatial streams are destined for the UE 350,they may be combined by the RX processor 356 into a single OFDM symbolstream. The RX processor 356 then converts the OFDM symbol stream fromthe time-domain to the frequency domain using a Fast Fourier Transform(FFT). The frequency domain signal includes a separate OFDM symbolstream for each subcarrier of the OFDM signal. The symbols on eachsubcarrier, and the reference signal, are recovered and demodulated bydetermining the most likely signal constellation points transmitted bythe base station 310. These soft decisions may be based on channelestimates computed by the channel estimator 358. The soft decisions arethen decoded and deinterleaved to recover the data and control signalsthat were originally transmitted by the base station 310 on the physicalchannel. The data and control signals are then provided to thecontroller/processor 359, which implements layer 3 and layer 2functionality.

The controller/processor 359 can be associated with a memory 360 thatstores program codes and data. The memory 360 may be referred to as acomputer-readable medium. In the UL, the controller/processor 359provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, and control signalprocessing to recover IP packets from the EPC 160. Thecontroller/processor 359 is also responsible for error detection usingan ACK or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DLtransmission by the base station 310, the controller/processor 359provides RRC layer functionality associated with system information (forexample, MIB, SIBs) acquisition, RRC connections, and measurementreporting; PDCP layer functionality associated with headercompression/decompression, and security (ciphering, deciphering,integrity protection, integrity verification); RLC layer functionalityassociated with the transfer of upper layer PDUs, error correctionthrough ARQ, concatenation, segmentation, and reassembly of RLC SDUs,re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; andMAC layer functionality associated with mapping between logical channelsand transport channels, multiplexing of MAC SDUs onto TBs,demultiplexing of MAC SDUs from TBs, scheduling information reporting,error correction through HARQ, priority handling, and logical channelprioritization.

Channel estimates derived by a channel estimator 358 from a referencesignal or feedback transmitted by the base station 310 may be used bythe TX processor 368 to select the appropriate coding and modulationschemes, and to facilitate spatial processing. The spatial streamsgenerated by the TX processor 368 may be provided to different antenna352 via separate transmitters 354TX. Each transmitter 354TX may modulatean RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a mannersimilar to that described in connection with the receiver function atthe UE 350. Each receiver 318RX receives a signal through its respectiveantenna 320. Each receiver 318RX recovers information modulated onto anRF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 thatstores program codes and data. The memory 376 may be referred to as acomputer-readable medium. In the UL, the controller/processor 375provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover IP packets from the UE 350. IP packets from thecontroller/processor 375 may be provided to the EPC 160. Thecontroller/processor 375 is also responsible for error detection usingan ACK or NACK protocol to support HARQ operations.

At least one of the TX processor 368, the RX processor 356, and thecontroller/processor 359 may be configured to perform aspects inconnection with communicating component 198 of FIG. 1.

At least one of the TX processor 316, the RX processor 370, and thecontroller/processor 375 may be configured to perform aspects inconnection with configuring component 199 of FIG. 1.

Some wireless communication technologies, such as LTE, support dedicatedbroadcast carriers. For example, in LTE, a carrier can be downlink-only,multimedia broadcast multicast service (MBMS)-only (for example, nounicast support). This can be similar in spirit to MB standards likeDVB-T, ATSC. Content can typically be free-to-air, where receivers maynot need to be registered with the network or have credentials (such assubscriber identity module (SIM) credentials) to receive the service(for example, TV service, car or automobile related broadcastinformation). In many countries around the world, the channelization ofbroadcast frequency bands for MB services is in units of bandwidths thatare not compatible with LTE bandwidths. For example, LTE supports systembandwidths of 1.4, 3, 5, 10, 15, 20 megahertz (MHz), which correspond to6, 15, 25, 50, 75 and 100 physical resource blocks (PRBs). In Europe,for example, channelization for MB service channels may be in chunks ofbandwidth of 8, 7, 6 MHz. For deploying in some regions and somefrequency bands, aspects described herein relate to supporting these MBbandwidths in the radio access technology (for example, NR, LTE).

FIG. 4 is a flowchart of an example of a method 400 for determining atime period for switching a common beam in accordance with some aspectsof the present disclosure. The method 400 may be performed by a UE (suchas the UE 104, the wireless communication device 700, or the wirelesscommunication device 800). In some examples, the method 400 may beperformed by a portion of a UE 104, wireless communication device 700,or wireless communication device 800, such as including the memory 360,the memory 708, the TX processor 368, the RX processor 356, thecontroller/processor 359, the processor 706, or other componentsdescribed herein.

In block 402, the UE communicates with a base station over multiplefrequency bands using a first beam. For example, the UE 104 can beconfigured with multiple frequency bands for communicating with the basestation 102 or other base stations. In some implementations, thecommunicating component 198 (which may include or operate in conjunctionwith one or more of the TX processor 368, the RX processor 356, thecontroller/processor 359, the memory 360, the receiver or transmitter354, the modem 702, the radio 704, the processor 706, the memory 708,the reception component 808, the transmission component 810, or othercomponents described herein) can communicate with the base station overthe multiple frequency bands using the first beam. In some examples, themultiple frequency bands may correspond to CCs configured by the basestation (for example, in a CA mode or a dual connectivity or multipleconnectivity mode, among other examples). In addition, in some examples,communicating component 198 can concurrently communicate over themultiple frequency bands, which may include concurrently receivingdownlink communications from the base station over the multiplefrequency bands using the first beam, concurrently transmitting uplinkcommunications to the base station over the multiple frequency bandsusing the first beam, or receiving communications from the base stationover a first frequency band of the multiple frequency bands whileconcurrently transmitting communications to the base station over asecond frequency band of the multiple frequency bands using the firstbeam.

In some examples, communicating component 198 can determine the firstbeam, based on a beam indicated to the base station 102, as a beam thatthe UE 104 selects during a beam training procedure. The selected beammay correspond to a beam transmitted by the base station 102 or acorresponding (for example, reciprocal) receive beam. In anotherexample, communicating component 198 can select a transmit beam andreceive beam pair (“transmit/receive beam pair”) and can indicate theselected beam pair to the base station 102. In any case, for example,communicating component 198 can communicate with the base station 102using the appropriate beam. In addition, communicating component 198 canuse the beam as a common beam for the multiple frequency bands.

As described, as the UE 104 moves locations with respect to the basestation 102, other beams can become more desirable and the UE 104 maydetermine, or be instructed (for example, by the base station), toswitch beams. In method 400, optionally at block 404, UE 104 candetermine to switch from the first beam to a second beam. In an aspect,beam switching component 816, for example, in conjunction withcommunicating component 198, one or more of the TX processor 368, the RXprocessor 356, or the controller/processor 359, the memory 360, thereceiver or transmitter 354, modem 702, radio 704, processor 706, memory708, reception component 808, transmission component 810, or othercomponents, can determine to switch from the first beam to the secondbeam to communicate over the multiple frequency bands. For example, beamswitching component 816 can determine to switch from the first beam tothe second beam based on beam switching criteria configured for the UE104, which may be configured at the UE 104 (for example, based on aconfiguration received from base station 102 or otherwise). In someexamples, beam switching component 816 can determine to switch from thefirst beam to the second beam based on at least one of an instructionreceived from the base station 102 (for example, an indication of beamswitching at the base station 102), comparing measurements of signalsreceived from the base station 102 based on the first and second beams,or other examples.

If a UE 104 has a common beam across multiple frequency bands (forexample, in CA or other scenarios), a large maximum receive timedifference (MRTD) may lead to large performance degradation. Forexample, the UE 104 may not be able to confine the beam switches insidethe CP, and receive or transmit discontinuities may appear in the middleof the symbols on some CCs. Furthermore, the UE beam switches can betransparent to the network so the network may not be aware of beamswitches. In frequency range 2 (FR2) for inter band CA with common beammanagement (CBM), different base station beams from a base station mayreach the UE 104 through different paths. As a result, when base stationswitches its TX beam, the UE can change its RX beam and reception timeto receive signal with the new TX beam. As the UE receives these bandswith a common beam, when base station switches its beam, UE cansimultaneously change the RX beams for all FR2 bands (for example, as acommon beam). If RTD among these bands is greater than a threshold (forexample, a timing of CP), the UE may lose a symbol on the other bands inthis CA scenario. Thus, according to aspects described herein,communicating component 198 can determine a time period to switch thecommon beam that mitigate communication disruptions on the multiplefrequency bands.

As such, for example, in method 400, optionally at block 406, UE 104 candetermine a time period during which to switch from the first beam tothe second beam. In some aspects, time period determining component 812,for example, in conjunction with communicating component 198, one ormore of the TX processor 368, the RX processor 356, or thecontroller/processor 359, the memory 360, the receiver or transmitter354, modem 702, radio 704, processor 706, memory 708, receptioncomponent 808, transmission component 810, or other components, candetermine the time period during which to switch from the first beam tothe second beam. As described above and further herein, the time periodcan be one of a limited number of time periods within a specifiedduration during which the UE is allowed to switch the first beam to thesecond beam or can correspond to, or be otherwise based on, a timingreference associated with a reference band.

For example, time period determining component 812 can determine thetime period based on a limited number or selection of time periods. Forexample, time period determining component 812 can determine the timeperiod based on a limited number or selection of symbols (for example,in a given slot or otherwise). Moreover, for example, time perioddetermining component 812 can determine the time period based on thelimited number or selection of time periods to lessen possibledisruption in communications over at least some of the multiplefrequency bands. Moreover, in some examples, time period determiningcomponent 812 can determine the time period(s) for a specified durationand may be consecutive or non-consecutive time periods within thespecified duration. For example, the specified duration may beconfigured for the UE 104 by the base station 102 or may be otherwiseknown by, or stored in an implementation or configuration of, the UE104. In one example, the specified duration may be a slot of multiplesymbols, and the limited number of time periods can include one or moreof the multiple symbols in the slot. In another example, time perioddetermining component 812, as described further herein, can determinethe time period based on a reference band, which may be one of themultiple frequency bands determined as the reference band for a timingreference.

In the example described above in FR2, the UE 104 can use one frequencyband's (for example, the reference band's) timing as the referencetiming and use that to change or switch beams for all FR2 bands that itreceives with the common beam. In some examples, time period determiningcomponent 812 can limit the number of symbols due to UE's autonomousbeam switch (which can be transparent to the network) and define thesymbols where UE is allowed to perform autonomous beam switch. Forexample, the time period determining component 812 can effectively limitautonomous RX beam switch in time periods that minimize or lessen impactnetwork performance, such as by limiting the time periods to gap symbolsbetween downlink and uplink in one or more slots (also referred to asUL/DL guard symbols). In one example, the UE 104 can report the actualRTD to the base station 102, and the base station 102 can accordinglyset the UL/DL guard symbols based on the actual reported RTD (or not setthe UL/DL guard symbols where the RTD is less than the CP).

In another example, time period determining component 812 can limit thenumber of symbols to given symbols of given subframes, which can bedefined based on a function of one or more parameters (for example,symbol X of slot N where N can be 0 modulo Z). In another example, timeperiod determining component 812 can limit the number of symbols tothose that do not include particular communications or channels, such asSSBs, PDCCH search spaces, RSs, or other examples. This can bebeneficial as PDCCH may trigger bandwidth part (BWP) switching,transmission control indicator (TCI) update, PDCCH-ordered physicalrandom access channel (PRACH), or other examples of time criticalcommunications. As such, time period determining component 812 candetermine to exclude such symbols from the time periods for beamswitching to avoid disrupting the time critical communications.

In method 400, at block 408, UE 104 can switch from the first beam tothe second beam during the time period. In some aspects, beam switchingcomponent 816, for example, in conjunction with communicating component198, one or more of the TX processor 368, the RX processor 356, or thecontroller/processor 359, the memory 360, the receiver or transmitter354, modem 702, radio 704, processor 706, memory 708, receptioncomponent 808, transmission component 810, or other components, canswitch from the first beam to the second beam during the time period,where the time period can be one or more of the time periods describedabove (for example, one of a limited number of time periods within aspecified duration during which the UE is allowed to switch the firstbeam to the second beam or based on a timing reference associated with areference band). For example, during the time period, beam switchingcomponent 816 can switch the beam by modifying the beamforming ofantenna resources to achieve the second beam for communicating with thebase station 102. As described, the beam switching may result in somedropped symbols on some of the frequency bands (for example, frequencybands that are not the reference band for beam switching), but timeperiod determining component 812 can determine to perform the switchingover given symbols that result in minimizing communication disruption.

FIG. 5 is a flowchart of an example of a method 500 for determining areference band for switching a common beam in accordance with someaspects of the present disclosure. The method 500 may be performed by aUE (such as the UE 104, the wireless communication device 700, thewireless communication device 800). In some examples, the method 500 maybe performed by a portion of a UE 104, wireless communication device700, or wireless communication device 800, such as by the memory 360,memory 708, the TX processor 368, the RX processor 356, or thecontroller/processor 359, processor 706, or other components.

In method 500, at block 502, UE 104 can communicate with a base stationover multiple frequency bands using a first beam. In some aspects,communicating component 198, for example, in conjunction with one ormore of the TX processor 368, the RX processor 356, or thecontroller/processor 359, the memory 360, the receiver or transmitter354, modem 702, radio 704, processor 706, memory 708, receptioncomponent 808, transmission component 810, or other components, cancommunicate with the base station over multiple frequency bands usingthe first beam. For example, communicating component 198 can communicateusing the first beam as described above with reference to block 402 ofmethod 400 of FIG. 4.

In method 500, optionally at block 504, UE 104 can determine to switchfrom the first beam to a second beam. In some aspects, beam switchingcomponent 816, for example, in conjunction with communicating component198, one or more of the TX processor 368, the RX processor 356, or thecontroller/processor 359, the memory 360, the receiver or transmitter354, modem 702, radio 704, processor 706, memory 708, receptioncomponent 808, transmission component 810, or other components, candetermine to switch from the first beam to the second beam. For example,beam switching component 816 can determine to switch from the first beamto the second beam as described above with reference to block 404 ofmethod 400 of FIG. 4.

In method 500, optionally at block 506, UE 104 can determine a referenceband from the multiple frequency bands to use as a timing reference forswitching from the first beam to the second beam. In some aspects,reference band determining component 814, for example, in conjunctionwith communicating component 198, one or more of the TX processor 368,the RX processor 356, or the controller/processor 359, the memory 360,the receiver or transmitter 354, modem 702, radio 704, processor 706,memory 708, reception component 808, transmission component 810, orother components, can determine the reference band from the multiplefrequency bands to use as the timing reference for switching from thefirst beam to the second beam. For example, reference band determiningcomponent 814 can determine which of the multiple frequency bands to useas the reference band based on an indication received from the basestation 102 or based on other considerations of the multiple frequencybands, as described herein. For example, reference band determiningcomponent 812 can compare aspects or parameters of the multiplefrequency bands with one another to determine the reference band.

In some examples, reference band determining component 814 can determinethe reference band based on explicit signaling from the base station102. For example, as described further herein, the base station 102 (forexample, or a network component via the base station 102) can explicitlyinform the UE 104 about the reference band, or can explicitly inform theUE 104 about the non-reference bands (for example, the bands whosesymbols can be dropped). In an example, where the base station 102informs the UE 104 about the non-reference bands, UE 104 can determinethe reference band to be a band other than the non-reference bandsand/or based on comparing parameters, as described, of the bands notindicated as non-reference bands. In this example, when performing beamswitching, the UE may be dropping symbols in UL or DL on particular CCs(for example, the non-reference frequency bands). In another example,reference band determining component 814 can determine the referenceband as the band where UE 104 measured signal strength or quality (RSRP,SINR, RSRQ, or other examples) and reported to the base station (or anassociated a serving cell) most recently or the band with the betterSINR or higher throughput. In either case, for example, the base station102 can also be aware of the determined reference band based on UE'sreport of the measured signal strength or quality.

In another example, reference band determining component 814 candetermine the reference band based on implicit parameters orconsiderations. For example, reference band determining component 814can determine the reference band as the frequency band of the multiplefrequency bands that has the lower index (for example, where the indexcan relate to an index of the band in a configuration received from thebase station 102 or otherwise known at the UE). In another example,reference band determining component 814 can determine the referenceband as the frequency band of the multiple frequency bands that includesthe center frequency. In another example, reference band determiningcomponent 814 can determine the reference band as the frequency band ofthe multiple frequency bands where PDCCH search space is more frequent(for example, where the PDCCH search space is configured more frequentlyover a set of time resources, such as over one or more slots or symbolsof one or more slots). In another example, reference band determiningcomponent 814 can determine the reference band as the frequency band ofthe multiple frequency bands where UE received most PDCCHs, for example,the band where UE reported most ACK/NACKs or PUSCHs for PDCCH, which maybe an explicit selection.

In another example, reference band determining component 814 candetermine the reference band as the frequency band of the multiplefrequency bands that has channels with higher priority. For example,reference band determining component 814 can determine the priority forthe channels for determining the reference band based on various rules.For example, reference band determining component 814 can determine thepriority for the channels based on channel type of channels transmittedover the band (for example, PUCCH can have a higher priority than SRS,which can have a higher priority than PUSCH). In another example,reference band determining component 814 can determine the priority forthe channels based on channel contents (for example, channels fortransmitting ACK/NACK can have higher priority than channels fortransmitting SR, which can have higher priority than channels fortransmitting RI, which can have higher priority than channels fortransmitting CQI). In another example, reference band determiningcomponent 814 can determine the priority for the channels based onreference signal type (for example, channels for transmitting DM-RS canhave higher priority than channels for transmitting phase trackingreference signal (PTRS), which can have higher priority than channelsfor transmitting other RSs). In another example, reference banddetermining component 814 can determine the priority for the channelsbased on subcarrier spacing (SCS) (for example, channels having high SCScan have higher priority than channels having low SCS). In someexamples, higher SCS may be more vulnerable to part of symbol/slotmissing and lower SCS may support delay tolerant services. In anotherexample, reference band determining component 814 can determine thepriority for the channels based on a number of symbols for the band (forexample, channels for channels having a low number of symbols can havehigher priority than channels for channels having a high number ofsymbols in a similar time period). In another example, reference banddetermining component 814 can determine the priority for the channelsbased on whether DL beam RSs are included (for example, channels on CCwith DL beam RS can have higher priority than channels on other CCs). Inanother example, reference band determining component 814 can determinethe priority for the channels based on whether feedback is receivedcorresponding to a higher or lower SCS (for example, channels for whichACK/NACK corresponds to higher PDSCH SCS can have higher priority thanchannels for which ACK/NACK corresponds to lower PDSCH SCS). In anotherexample, reference band determining component 814 can determine thepriority for the channels based on a number of instances of feedbackreceived (for example, channels for which a high number of ACK/NACKs arereceived can have higher priority than channels for which a low numberof ACK/NACKs are received over a similar time period). In anotherexample, reference band determining component 814 can determine thepriority for the channels based on channel quality indicator (CQI) partcorresponding to the channel (for example, channels for transmitting CQIpart-I can have a higher priority than channels for transmitting CQIpart-II). In another example, reference band determining component 814can determine the priority for the channels based on whether the channelor corresponding signal is scheduled or autonomous (for example,scheduled channel/signal can have higher priority than >autonomouschannel/signal).

In addition, in some examples, in determining the channel priority,reference band determining component 814 can update TCI of lowerpriority channel/signal on a non-reference band to follow the TCI ofhigher priority channel/signal on the reference band. In addition, forexample, at least some of the same channels/signals may be transmittedon multiple frequency bands, and other considerations may be used todetermine priority for the reference band, as described above.

In method 500, optionally at block 508, UE 104 can determine timingassociated with communications over the reference band. In some aspects,beam switching component 816, for example, in conjunction withcommunicating component 198, one or more of the TX processor 368, the RXprocessor 356, or the controller/processor 359, the memory 360, thereceiver or transmitter 354, modem 702, radio 704, processor 706, memory708, reception component 808, transmission component 810, or othercomponents, can determine timing associated with communications over thereference band. For example, beam switching component 816 can determinethe timing as a symbol location, slot boundary, or other time instancerelated to communications configured over the reference band.

In method 500, optionally at block 510, UE 104 can determine a timeperiod during which to switch the first beam to the second beam based onthe timing. In some aspects, beam switching component 816, for example,in conjunction with communicating component 198, one or more of the TXprocessor 368, the RX processor 356, or the controller/processor 359,the memory 360, the receiver or transmitter 354, modem 702, radio 704,processor 706, memory 708, reception component 808, transmissioncomponent 810, or other components, can determine the time period duringwhich to switch the first beam to the second beam based on the timing.For example, beam switching component 816 can determine the time periodas a particular symbol, slot, or other examples, for performing beamswitching, which can be based on the timing associated with thereference band. In some examples, the time period may be configured bythe base station in communications associated with the reference band.In some examples, beam switching component 816 can determine the timeperiod to minimize disruption of communications in the reference band,such as a time period including UL DL gap (for example, guard) symbols,not including particular communication channels, or other examples, asdescribed above.

In method 500, at block 512, UE 104 can switch, during the time period,from the first beam to the second beam during the time period. In someaspects, beam switching component 816, for example, in conjunction withcommunicating component 198, one or more of the TX processor 368, the RXprocessor 356, or the controller/processor 359, the memory 360, thereceiver or transmitter 354, modem 702, radio 704, processor 706, memory708, reception component 808, transmission component 810, or othercomponents, can switch, during the time period, from the first beam tothe second beam during the time period. For example, during the timeperiod, beam switching component 816 can switch the beam by modifyingthe beamforming of antenna resources to achieve the second beam forcommunicating with the base station 102. As described, the beamswitching may result in some dropped symbols on some of the frequencybands (for example, frequency bands that are not the reference band forbeam switching), but reference band determining component 814 candetermine the reference band over which to perform the switching sosymbols over the reference band are not lost, which can result inminimizing communication disruption.

FIG. 6 is a flowchart of an example of a method 600 for configuring areference band for switching a common beam in accordance with someaspects of the present disclosure. The method 600 may be performed by abase station (such as the base station 102, the wireless communicationdevice 700, the wireless communication device 900). In some examples,the method 600 may be performed by a portion of a base station 102,wireless communication device 700, or wireless communication device 900,such as by the memory 376, memory 708, the TX processor 316, the RXprocessor 370, or the controller/processor 375, processor 706, or othercomponents.

In method 600, at block 602, base station 102 can communicate with a UEover multiple frequency bands using a first beam. In some aspects,configuring component 199, for example, in conjunction with one or moreof the TX processor 316, the RX processor 370, or thecontroller/processor 375, the memory 376, the receiver or transmitter318, modem 702, radio 704, processor 706, memory 708, receptioncomponent 908, transmission component 910, or other components, cancommunicate with the UE over multiple frequency bands using the firstbeam. For example, the base station 102 can configure multiple frequencybands for communicating with the UE 104. In some examples, the multiplefrequency bands may correspond to CCs configured by the base station(for example, in CA, dual connectivity or multiple connectivity, amongother examples). In some examples, configuring component 199 candetermine the first beam based on a beam indicated by the UE 104 (forexample, as a selected beam selected by the UE 104) during a beamtraining procedure. The selected beam may correspond to a beamtransmitted by the base station 102 or a corresponding (for example,reciprocal) receive beam determined by the UE 104. In addition,configuring component 199 can use the beam as a common beam for themultiple frequency bands.

As described, as the UE 104 moves locations with respect to the basestation 102, other beams can become more desirable and the UE 104 maydetermine, or be instructed, to switch beams. As such, switching beamsat the UE 104 may include the UE 104 determining a reference band to usefor switching the beam. In some examples, base station 102 can instructthe UE 104 on the reference band or one or more parameters fordetermining the reference band. In method 600, at block 604, basestation 102 can transmit, to the UE, an indication of one or moreparameters for determining a reference band of the multiple frequencybands to use as a timing reference for switching beams for communicatingover the multiple frequency bands. In some aspects, reference bandconfiguring component 912, for example, in conjunction with configuringcomponent 199, one or more of the TX processor 316, the RX processor370, or the controller/processor 375, the memory 376, the receiver ortransmitter 318, modem 702, radio 704, processor 706, memory 708,reception component 908, transmission component 910, or othercomponents, can transmit, to the UE 104, the indication of one or moreparameters for determining a reference band of the multiple frequencybands to use as a timing reference for switching beams for communicatingover the multiple frequency bands.

In some examples, reference band configuring component 912 can indicatethe reference band to the UE 104, can indicate one or more non-referencebands, or other examples, as described above. For example, referenceband configuring component 912 can indicate the band(s) in aconfiguration using radio resource control (RRC) signaling, media accesscontrol (MAC) control element (CE), downlink control information (DCI),or other examples. In addition, for example, reference band configuringcomponent 912 can determine the reference band to configure based onsignal strength or quality measurements received from the UE 104. Forexample, reference band configuring component 912 can determine thereference band as the frequency band for which the most recent signalstrength or quality report is received from the UE 104, the frequencyband having a highest measured signal strength or quality, or otherexamples as described herein.

FIG. 7 shows a block diagram of an example wireless communication device700. In some implementations, the wireless communication device 700 canbe an example of a device for use in a UE such as one of the UEs 104described with reference to FIG. 1. In some implementations, thewireless communication device 700 can be an example of a device for usein an base station such as the base station 102 described with referenceto FIG. 1. The wireless communication device 700 is capable oftransmitting (or outputting for transmission) and receiving wirelesscommunications (for example, in the form of wireless packets). Forexample, the wireless communication device can be configured to transmitand receive packets in the form of packet data convergence protocol(PDCP) protocol data units (PDUs) and medium access control (MAC) PDUs,or other examples.

The wireless communication device 700 can be, or can include, a chip,system on chip (SoC), chipset, package or device that includes one ormore modems 702, (collectively “the modem 702”), which can include aWWAN modem (for example, a 3GPP 4G LTE or 5G compliant modem). In someimplementations, the wireless communication device 700 also includes oneor more radios 704 (collectively “the radio 704”). In someimplementations, the wireless communication device 700 further includesone or more processors, processing blocks or processing elements 706(collectively “the processor 706”) and one or more memory blocks orelements 708 (collectively “the memory 708”).

The modem 702 can include an intelligent hardware block or device suchas, for example, an application-specific integrated circuit (ASIC) amongother possibilities. The modem 702 is generally configured to implementa PHY layer. For example, the modem 702 is configured to modulatepackets and to output the modulated packets to the radio 704 fortransmission over the wireless medium. The modem 702 is similarlyconfigured to obtain modulated packets received by the radio 704 and todemodulate the packets to provide demodulated packets. In addition to amodulator and a demodulator, the modem 702 may further include digitalsignal processing (DSP) circuitry, automatic gain control (AGC), acoder, a decoder, a multiplexer and a demultiplexer. For example, whilein a transmission mode, data obtained from the processor 706 is providedto a coder, which encodes the data to provide encoded bits. The encodedbits are then mapped to points in a modulation constellation (using aselected MCS) to provide modulated symbols. The modulated symbols maythen be mapped to a number NSS of spatial streams or a number NSTS ofspace-time streams. The modulated symbols in the respective spatial orspace-time streams may then be multiplexed, transformed via an inversefast Fourier transform (IFFT) block, and subsequently provided to theDSP circuitry for Tx windowing and filtering. The digital signals maythen be provided to a digital-to-analog converter (DAC). The resultantanalog signals may then be provided to a frequency upconverter, andultimately, the radio 704. In implementations involving beamforming, themodulated symbols in the respective spatial streams are precoded via asteering matrix prior to their provision to the IFFT block.

While in a reception mode, digital signals received from the radio 704are provided to the DSP circuitry, which is configured to acquire areceived signal, for example, by detecting the presence of the signaland estimating the initial timing and frequency offsets. The DSPcircuitry is further configured to digitally condition the digitalsignals, for example, using channel (narrowband) filtering, analogimpairment conditioning (such as correcting for I/Q imbalance), andapplying digital gain to ultimately obtain a narrowband signal. Theoutput of the DSP circuitry may then be fed to the AGC, which isconfigured to use information extracted from the digital signals, forexample, in one or more received training fields, to determine anappropriate gain. The output of the DSP circuitry also is coupled withthe demodulator, which is configured to extract modulated symbols fromthe signal and, for example, compute the logarithm likelihood ratios(LLRs) for each bit position of each subcarrier in each spatial stream.The demodulator is coupled with the decoder, which may be configured toprocess the LLRs to provide decoded bits. The decoded bits from all ofthe spatial streams are then fed to the demultiplexer fordemultiplexing. The de-multiplexed bits may then be descrambled andprovided to the MAC layer (the processor 706) for processing, evaluationor interpretation.

The radio 704 generally includes at least one radio frequency (RF)transmitter (or “transmitter chain”) and at least one RF receiver (or“receiver chain”), which may be combined into one or more transceivers.For example, the RF transmitters and receivers may include various DSPcircuitry including at least one power amplifier (PA) and at least onelow-noise amplifier (LNA), respectively. The RF transmitters andreceivers may, in turn, be coupled to one or more antennas. For example,in some implementations, the wireless communication device 700 caninclude, or be coupled with, multiple transmit antennas (each with acorresponding transmit chain) and multiple receive antennas (each with acorresponding receive chain). The symbols output from the modem 702 areprovided to the radio 704, which then transmits the symbols via thecoupled antennas. Similarly, symbols received via the antennas areobtained by the radio 704, which then provides the symbols to the modem702.

The processor 706 can include an intelligent hardware block or devicesuch as, for example, a processing core, a processing block, a centralprocessing unit (CPU), a microprocessor, a micro-controller, a digitalsignal processor (DSP), an application-specific integrated circuit(ASIC), a programmable logic device (PLD) such as a field programmablegate array (FPGA), discrete gate or transistor logic, discrete hardwarecomponents, or any combination thereof designed to perform the functionsdescribed herein. The processor 706 processes information receivedthrough the radio 704 and the modem 702, and processes information to beoutput through the modem 702 and the radio 704 for transmission throughthe wireless medium. For example, the processor 706 may implement acontrol plane and MAC layer configured to perform various operationsrelated to the generation and transmission of PDUs, frames or packets.The MAC layer is configured to perform or facilitate the coding anddecoding of frames, spatial multiplexing, space-time block coding(STBC), beamforming, and OFDMA resource allocation, among otheroperations or techniques. In some implementations, the processor 706 maygenerally control the modem 702 to cause the modem to perform variousoperations described above.

The memory 708 can include tangible storage media such as random-accessmemory (RAM) or read-only memory (ROM), or combinations thereof. Thememory 708 also can store non-transitory processor- orcomputer-executable software (SW) code containing instructions that,when executed by the processor 706, cause the processor to performvarious operations described herein for wireless communication,including the generation, transmission, reception and interpretation ofPDUs, frames or packets. For example, various functions of componentsdisclosed herein, or various blocks or steps of a method, operation,process or algorithm disclosed herein, can be implemented as one or moremodules of one or more computer programs.

FIG. 8 shows a block diagram of an example wireless communication device800 according to some implementations. In some implementations, thewireless communication device 800 is configured to perform any of theprocesses 400 or 500 described above with reference to FIGS. 4 and 5,respectively. In some implementations, the wireless communication device800 can be an example implementation of the wireless communicationdevice 700 described above with reference to FIG. 7. For example, thewireless communication device 800 can be a chip, SoC, chipset, packageor device that includes at least one processor and at least one modem(for example, a Wi-Fi (IEEE 802.11) modem or a cellular modem).

The wireless communication device 800 includes a reception component808, a communicating component 198, and a transmission component 810.The communicating component 198 may further optionally include one ormore of a time period determining component 812, a reference banddetermining component 814, and/or a beam switching component 816.Portions of one or more of the components 812, 814, and 816, may beimplemented at least in part in hardware or firmware. In someimplementations, at least one of the components 812, 814, and 816, isimplemented at least in part as software stored in a memory (such as thememory 708). For example, portions of one or more of the components 812,814, and 816, can be implemented as non-transitory instructions or codeexecutable by a processor (such as the processor 706) to perform thefunctions or operations of the respective component.

The reception component 808 is configured to receive RX signals fromanother wireless communication device. In some implementations, the RXsignals may include a configuration or parameters for switching a commonbeam. The communicating component 198 is configured to switch a beamused for receiving RX signals or transmitting TX signals viatransmission component 810, as described herein. Moreover, as described,time period determining component 812 can determine a time period forswitching the common beam, reference band determining component 814 candetermine a reference band for switching the common beam, or beamswitching component 816 can switch the common beam.

FIG. 9 shows a block diagram of an example wireless communication device900 according to some implementations. In some implementations, thewireless communication device 900 is configured to perform process 600described above with reference to FIG. 6. In some implementations, thewireless communication device 900 can be an example implementation ofthe wireless communication device 700 described above with reference toFIG. 7. For example, the wireless communication device 900 can be achip, SoC, chipset, package or device that includes at least oneprocessor and at least one modem (for example, a Wi-Fi (IEEE 802.11)modem or a cellular modem).

The wireless communication device 900 includes a reception component908, a configuring component 199, and a transmission component 910. Theconfiguring component 199 may further include a reference bandconfiguring component 912. Portions of one or more of the components 912may be implemented at least in part in hardware or firmware. In someimplementations, at least one of the components 912 is implemented atleast in part as software stored in a memory (such as the memory 708).For example, portions of one or more of the components 912 can beimplemented as non-transitory instructions or code executable by aprocessor (such as the processor 706) to perform the functions oroperations of the respective component.

The reception component 808 is configured to receive RX signals fromanother wireless communication device. In some implementations, the RXsignals may include uplink signals received from a UE 104, where the UEcan switch a common beam used to transmit the uplink signals. Theconfiguring component 199 is configured to configure, via reference bandconfiguring component 912, a reference band for the UE to use inswitching the common beam.

The following aspects are illustrative only and aspects thereof may becombined with aspects of other embodiments or teaching described herein,without limitation.

Aspect 1 is a method for wireless communication by a UE includingcommunicating with a base station over multiple frequency bands using afirst beam, determining to switch the first beam to a second beam,determining a time period during which to switch the first beam to thesecond beam, where the time period is one of a limited number of timeperiods within a specified duration during which the UE is allowed toswitch the first beam to the second beam, and switching from the firstbeam to the second beam during the time period.

In Aspect 2, the method of Aspect 1 includes where determining the timeperiod includes determining the time period as one or more symbols of alimited number of symbols within the specified duration.

In Aspect 3, the method of Aspect 2 includes where determining the timeperiod includes determining the time period within a transmission gapbetween uplink and downlink communications.

In Aspect 4, the method of Aspect 3 includes reporting, to the basestation, a receive time difference, where the transmission gap is setbased on the receive transmit difference.

In Aspect 5, the method of any of Aspects 2 to 4 includes wheredetermining the time period as the one or more symbols includesdetermining the time period as the one or more symbols in a slot basedon a function of a slot index of the slot.

In Aspect 6, the method of any of Aspects 1 to 5 includes wheredetermining the time period includes determining the time period as oneor more symbols for communications other than symbols for at least oneof a synchronization signal block, a physical downlink control channelsearch space, or a reference signal.

In Aspect 7, the method of any of Aspects 1 to 6 includes wheredetermining the time period is based at least in part on receiving, fromthe base station, an indication of the time period.

In Aspect 8, the method of Aspect 7 includes where receiving theindication includes receiving, from the base station, the indicationover one or more of a control channel, system information, a MIB, aMAC-CE, or RRC signaling.

In Aspect 9, the method of any of Aspects 1 to 8 includes wheredetermining the time period is based at least in part on receiving, fromthe base station, one or more parameters for determining the timeperiod.

In Aspect 10, the method of any of Aspects 1 to 9 includes reporting, tothe base station, a difference between a first time at which a signal isreceived in a first band and a second time at which the signal isreceived in a second band.

Aspect 11 is a method for wireless communications includingcommunicating with a base station over multiple frequency bands using afirst beam, determining to switch the first beam to a second beam,determining a reference band from the multiple frequency bands to use asa timing reference for switching the first beam to the second beam,determining timing associated with communications over the referenceband, determining a time period during which to switch the first beam tothe second beam based on the timing, and switching, during the timeperiod, from the first beam to the second beam.

In Aspect 12, the method of Aspect 11 includes where determining thereference band includes receiving, from the base station, an indicationof the reference band to use as the timing reference for switchingbeams.

In Aspect 13, the method of any of Aspects 11 or 12 includes wheredetermining the reference band is based on receiving, from the basestation, an indication of one or more non-reference bands of themultiple frequency bands.

In Aspect 14, the method of any of Aspects 11 to 13 includes whereswitching from the first beam to the second beam includes droppingcommunications over symbols on one or more of the multiple frequencybands other than the reference band.

In Aspect 15, the method of any of Aspects 11 to 14 includes wheredetermining the reference band includes determining one of the multiplefrequency bands over which the UE most recently reports a signal metricto the base station as the reference band.

In Aspect 16, the method of Aspect 15 includes where the signal metricincludes one or more of a RSRP, a RSRQ, a SNR, a SINR, or a RSSI.

In Aspect 17, the method of any of Aspects 11 to 16 includes wheredetermining the reference band includes determining one of the multiplefrequency bands having a highest reported signal metric as the referenceband.

In Aspect 18, the method of Aspect 17 includes where the signal metricincludes one or more of a RSRP, a RSRQ, a SNR, a SINR, or a RSSI.

In Aspect 19, the method of any of Aspects 11 to 18 includes wheredetermining the reference band includes determining one of the multiplefrequency bands that has at least one of a lowest index, a centerfrequency, or a most frequent PDCCH search space.

In Aspect 20, the method of any of Aspects 11 to 19 includes wheredetermining the reference band includes determining one of the multiplefrequency bands that has one or more channels of a highest priority asthe reference band.

In Aspect 21, the method of Aspect 20 includes determining a priority ofchannels, to determine the one of the multiple frequency bands that haschannels of a highest priority, based on at least one of a channel typeof each of the channels, a SCS of each of the channels, a number ofsymbols in each of the channels, whether each of the channels is a beamreference, feedback in consideration of SCS for each of the channels, anumber of instances of feedback received for a PDCCH or a PDSCH for eachof the channels, a channel quality indicator, or whether each of thechannels is scheduled or autonomous.

Aspect 22 is a method for wireless communications includingcommunicating with a UE over multiple frequency bands using a firstbeam, and transmitting, to the UE, an indication of one or moreparameters for determining a reference band of the multiple frequencybands to use as a timing reference for switching beams for communicatingover the multiple frequency bands.

In Aspect 23, the method of Aspect 22 includes where the one or moreparameters include an indication of the reference band.

In Aspect 24, the method of any of Aspects 22 or 23 includes where theone or more parameters include an indication of one or morenon-reference bands of the multiple frequency bands.

In Aspect 25, the method of any of Aspects 22 to 24 includes determiningthe reference band as one of the multiple frequency bands over which theUE has most recently reported a signal metric.

In Aspect 26, the method of any of Aspects 22 to 25 includes determiningthe reference band as one of the multiple frequency bands having ahighest reported signal metric.

Aspect 27 is a method for wireless communication by a UE includingconcurrently communicating with a base station over multiple frequencybands using a same first beam, and switching, according to beamswitching criteria, from the first beam to a second beam during a timeperiod, where the time period is one of a limited number of time periodsduring which the UE is allowed to switch the first beam to the secondbeam within a specified duration, or based on a timing referenceassociated with a reference band of the multiple frequency bands.

In Aspect 28, the method of Aspect 27 includes where the time periodincludes one or more symbols of a limited number of symbols within thespecified duration, and dropping the one or more symbols within at leastone of the multiple frequency bands within the specified duration.

In Aspect 29, the method of Aspect 28 includes where the time period iswithin a transmission gap between uplink and downlink communications,and reporting, to the base station, a receive time difference between atime a first signal is received by the UE in a first frequency band ofthe multiple frequency bands and a time a second signal is received bythe UE in a second frequency band of the multiple frequency bands, wherethe transmission gap is set based on the receive time difference.

In Aspect 30, the method of any of Aspects 27 to 29 includes where thetime period consists of one or more symbols for communications otherthan symbols for at least one of a SSB, a PDCCH search space, or areference signal.

In Aspect 31, the method of any of Aspects 27 to 30 includes receiving,from the base station, an indication of the time period or one or moreparameters for determining the time period.

In Aspect 32, the method of any of Aspects 27 to 31 includes receiving,from the base station, at least one of an indication of the referenceband to use as the timing reference for switching beams or an indicationof one or more non-reference bands of the multiple frequency bands.

In Aspect 33, the method of any of Aspects 27 to 31 includes droppingcommunications over symbols on one or more of the multiple frequencybands other than the reference band during at least the switch from thefirst beam to the second beam.

In Aspect 34, the method of any of Aspects 27 to 33 includes where thereference band is associated with a highest signal metric of themultiple frequency bands in a most recent report, where the signalmetric includes one or more of a RSRP, a RSRQ, a SNR, a SINR, or a RSSI.

In Aspect 35, the method of any of Aspects 27 to 34 includes where thereference band is associated with one of the multiple frequency bandshaving a lowest index, a center frequency, or a most frequent PDCCHsearch space.

In Aspect 36, the method of any of Aspects 27 to 35 includes where thereference band is associated with one of the multiple frequency bandsthat has one or more channels of a highest priority, where the priorityof channels is based on at least one of respective channel types of thechannels, respective SCSs of the channels, respective numbers of symbolsin the channels, whether each of the channels is a beam reference,feedback for each of the channels, respective numbers of instances offeedback received for a PDCCH or a PDSCH for the channels, a channelquality indicator, or whether each of the channels is scheduled orautonomous.

Aspect 37 is an apparatus for wireless communication including atransceiver, a memory configured to store instructions, and one or moreprocessors communicatively coupled with the transceiver and the memory,where the one or more processors are configured to execute theinstructions to perform the operations of one or more methods in any ofAspects 1 to 36.

Aspect 38 is an apparatus for wireless communication including means forperforming the operations of one or more methods in any of Aspects 1 to36.

Aspect 39 is a computer-readable medium including code executable by oneor more processors to perform the operations of one or more methods inany of Aspects 1 to 36.

The specific order or hierarchy of blocks in the processes/flowchartsdisclosed is an illustration of example approaches. Based upon designpreferences, the specific order or hierarchy of blocks in theprocesses/flowcharts may be rearranged. Further, some blocks may becombined or omitted. The accompanying method claims present elements ofthe various blocks in a sample order, and are not meant to be limited tothe specific order or hierarchy presented.

The previous description is provided to enable any person of ordinaryskill in the art to practice the various aspects described herein.Various modifications to these aspects will be readily apparent to thoseof ordinary skill in the art, and the generic principles defined hereinmay be applied to other aspects. The claims are not intended to belimited to the aspects shown herein, but is to be accorded the fullscope consistent with the language claims, wherein reference to anelement in the singular is not intended to mean “one and only one”unless specifically so stated, but rather “one or more.” The word“exemplary” is used herein to mean “serving as an example, instance, orillustration.” Any aspect described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otheraspects. Unless specifically stated otherwise, the term “some” refers toone or more. Combinations such as “at least one of A, B, or C,” “one ormore of A, B, or C,” “at least one of A, B, and C,” “one or more of A,B, and C,” and “A, B, C, or any combination thereof” include anycombination of A, B, or C, and may include multiples of A, multiples ofB, or multiples of C. Specifically, combinations such as “at least oneof A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, andC,” “one or more of A, B, and C,” and “A, B, C, or any combinationthereof” may include A only, B only, C only, A and B only, A and C only,B and C only, or A and B and C, where any such combinations may containone or more members of any of A, B, or C. All structural and functionalequivalents to the elements of the various aspects described throughoutthis disclosure that are known or later come to be known to those ofordinary skill in the art are expressly incorporated herein by referenceand are intended to be encompassed by the claims. Moreover, nothingdisclosed herein is intended to be dedicated to the public regardless ofwhether such disclosure is explicitly recited in the claims. The words“module,” “mechanism,” “element,” “device,” and the like may not be asubstitute for the word “means.” As such, no claim element is to beconstrued as a means plus function unless the element is expresslyrecited using the phrase “means for.”

What is claimed is:
 1. An apparatus for wireless communication,comprising: a transceiver; a memory configured to store instructions;and one or more processors communicatively coupled with the memory andthe transceiver, wherein the one or more processors are configured toexecute the instructions to cause the apparatus to: concurrentlycommunicate with a base station over multiple frequency bands using asame first beam; and switch, according to beam switching criteria, fromthe first beam to a second beam during a time period, wherein the timeperiod is: one of a limited number of time periods during which theapparatus is allowed to switch the first beam to the second beam withina specified duration; or based on a timing reference associated with areference band of the multiple frequency bands.
 2. The apparatus ofclaim 1, wherein the time period includes one or more symbols of alimited number of symbols within the specified duration, and wherein theone or more processors are further configured to execute theinstructions to cause the apparatus to drop the one or more symbolswithin at least one of the multiple frequency bands within the specifiedduration.
 3. The apparatus of claim 2, wherein the time period is withina transmission gap between uplink and downlink communications, andwherein the one or more processors are further configured to execute theinstructions to cause the apparatus to report, to the base station, areceive time difference between a time a first signal is received by theapparatus in a first frequency band of the multiple frequency bands anda time a second signal is received by the apparatus in a secondfrequency band of the multiple frequency bands, wherein the transmissiongap is set based on the receive time difference.
 4. The apparatus ofclaim 1, wherein the time period consists of one or more symbols forcommunications other than symbols for at least one of a synchronizationsignal block (SSB), a physical downlink control channel (PDCCH) searchspace, or a reference signal.
 5. The apparatus of claim 1, wherein theone or more processors are further configured to execute theinstructions to cause the apparatus to receive, from the base station,an indication of the time period or one or more parameters fordetermining the time period.
 6. The apparatus of claim 1, wherein theone or more processors are further configured to execute theinstructions to cause the apparatus to receive, from the base station,at least one of an indication of the reference band to use as the timingreference for switching beams or an indication of one or morenon-reference bands of the multiple frequency bands.
 7. The apparatus ofclaim 1, wherein the one or more processors are configured to executethe instructions to cause the apparatus to drop communications oversymbols on one or more of the multiple frequency bands other than thereference band during at least the switch from the first beam to thesecond beam.
 8. The apparatus of claim 1, wherein the reference band isassociated with a highest signal metric of the multiple frequency bandsin a most recent report, wherein the signal metric includes one or moreof a reference signal received power (RSRP), a reference signal receivedquality (RSRQ), a signal-to-noise ratio (SNR), asignal-to-interference-and-noise ratio (SINR), or a received signalstrength indicator (RSSI).
 9. The apparatus of claim 1, wherein thereference band is associated with one of the multiple frequency bandshaving a lowest index, a center frequency, or a most frequent physicaldownlink control channel (PDCCH) search space.
 10. The apparatus ofclaim 1, wherein the reference band is associated with one of themultiple frequency bands that has one or more channels of a highestpriority, wherein the priority of channels is based on at least one ofrespective channel types of the channels, respective subcarrier spacings(SCSs) of the channels, respective numbers of symbols in the channels,whether each of the channels is a beam reference, feedback for each ofthe channels, respective numbers of instances of feedback received for aPDCCH or a PDSCH for the channels, a channel quality indicator, orwhether each of the channels is scheduled or autonomous.
 11. Anapparatus for wireless communication, comprising: a transceiver; amemory configured to store instructions; and one or more processorscommunicatively coupled with the memory and the transceiver, wherein theone or more processors are configured to execute the instructions tocause the apparatus to: communicate with a user equipment (UE) overmultiple frequency bands using a first beam; and transmit, to the UE, anindication of one or more parameters for determining a reference band ofthe multiple frequency bands to use as a timing reference for switchingbeams for communicating over the multiple frequency bands.
 12. Theapparatus of claim 11, wherein the one or more parameters include anindication of the reference band.
 13. The apparatus of claim 11, whereinthe one or more parameters include an indication of one or morenon-reference bands of the multiple frequency bands.
 14. The apparatusof claim 11, wherein the one or more processors are further configuredto execute the instructions to cause the apparatus to determine thereference band as one of the multiple frequency bands over which the UEhas most recently reported a signal metric.
 15. The apparatus of claim11, wherein the one or more processors are further configured to executethe instructions to cause the apparatus to determine the reference bandas one of the multiple frequency bands having a highest reported signalmetric.
 16. A method for wireless communication by a user equipment(UE), comprising: concurrently communicating with a base station overmultiple frequency bands using a same first beam; and switching,according to beam switching criteria, from the first beam to a secondbeam during a time period, wherein the time period is: one of a limitednumber of time periods during which the UE is allowed to switch thefirst beam to the second beam within a specified duration; or based on atiming reference associated with a reference band of the multiplefrequency bands.
 17. The method of claim 16, wherein the time periodincludes one or more symbols of a limited number of symbols within thespecified duration, and further comprising dropping the one or moresymbols within at least one of the multiple frequency bands within thespecified duration.
 18. The method of claim 17, wherein the time periodis within a transmission gap between uplink and downlink communications,and further comprising reporting, to the base station, a receive timedifference between a time a first signal is received by the UE in afirst frequency band of the multiple frequency bands and a time a secondsignal is received by the UE in a second frequency band of the multiplefrequency bands, wherein the transmission gap is set based on thereceive time difference.
 19. The method of claim 16, wherein the timeperiod consists of one or more symbols for communications other thansymbols for at least one of a synchronization signal block (SSB), aphysical downlink control channel (PDCCH) search space, or a referencesignal.
 20. The method of claim 16, further comprising receiving, fromthe base station, an indication of the time period or one or moreparameters for determining the time period.
 21. The method of claim 16,further comprising receiving, from the base station, at least one of anindication of the reference band to use as the timing reference forswitching beams or an indication of one or more non-reference bands ofthe multiple frequency bands.
 22. The method of claim 16, furthercomprising dropping communications over symbols on one or more of themultiple frequency bands other than the reference band during at leastthe switch from the first beam to the second beam.
 23. The method ofclaim 16, wherein the reference band is associated with a highest signalmetric of the multiple frequency bands in a most recent report, whereinthe signal metric includes one or more of a reference signal receivedpower (RSRP), a reference signal received quality (RSRQ), asignal-to-noise ratio (SNR), a signal-to-interference-and-noise ratio(SINR), or a received signal strength indicator (RSSI).
 24. The methodof claim 16, wherein the reference band is associated with one of themultiple frequency bands having a lowest index, a center frequency, or amost frequent physical downlink control channel (PDCCH) search space.25. The method of claim 16, wherein the reference band is associatedwith one of the multiple frequency bands that has one or more channelsof a highest priority, wherein the priority of channels is based on atleast one of respective channel types of the channels, respectivesubcarrier spacings (SCSs) of the channels, respective numbers ofsymbols in the channels, whether each of the channels is a beamreference, feedback for each of the channels, respective numbers ofinstances of feedback received for a PDCCH or a PDSCH for the channels,a channel quality indicator, or whether each of the channels isscheduled or autonomous.
 26. A method for wireless communications,comprising: communicating with a user equipment (UE) over multiplefrequency bands using a first beam; and transmitting, to the UE, anindication of one or more parameters for determining a reference band ofthe multiple frequency bands to use as a timing reference for switchingbeams for communicating over the multiple frequency bands.
 27. Themethod of claim 26, wherein the one or more parameters include anindication of the reference band or an indication of one or morenon-reference bands of the multiple frequency bands.
 28. The method ofclaim 26, wherein the one or more parameters include an indication ofone or more non-reference bands of the multiple frequency bands.
 29. Themethod of claim 26, further comprising determining the reference band asone of the multiple frequency bands over which the UE has most recentlyreported a signal metric.
 30. The method of claim 26, further comprisingdetermining the reference band as one of the multiple frequency bandshaving a highest reported signal metric.